Toward a New Generation of Intermediate-Temperature Fuel Cells

Solid oxide fuel cells (SOFCs) have potential to be the cleanest and most efficient option for direct conversion to electricity and heat of a wide variety of fuels, from hydrogen to hydrocarbons, coal gas, and bio-derived fuels. However, their commercialization hinges on rational design of novel materials of exceptional functionalities at lower temperatures to dramatically reduce the cost while enhancing performance and durability. To accomplish this goal, it is imperative to gain a fundamental understanding of the mechanisms of charge and mass transport along surfaces, across interfaces, and through porous electrodes in fuel cell systems. Further, new protocols must be developed to control materials structure, composition, and morphology over multiple length scales, thus producing nano-porous materials with more accessible surfaces of much higher functionalities and with shorter diffusion distances for greatly enhanced rate capabilities. Recently, we have fabricated and tested an electrode architecture derived from nanofibers of active cathode materials with enhanced electrochemical performance, nano-structured Sm-doped ceria electrolyte membranes with high ionic conductivity, and membrane samples of proton and oxygen ion conducting electrolytes to study nanoionics effects at heterogeneous interfaces.